using System;
using System.Collections.Generic;
using System.Text;

namespace Assignment
{
    class Program
    {
        static void Main(string[] args)
        {
            double x, y;
            x = y = 2;//从右向左赋值，x、y的值都是2
            x /= 0.5;
            y -= 2;
            Console.WriteLine(x - y);
        }
    }
}